1. Field of the Invention
The present invention relates to an improved dual-shaft synchronous movement device. The dual-shaft synchronous movement device includes a first shaft and a second shaft and an assembly of rotors and cooperative inextensible/non-contractible flexible plates wound on the rotors. In operation, the first and second shafts are synchronously rotated to overcome the problem of the conventional transmission mechanism that the wires are likely to slip or deflect from the rollers.
2. Description of the Related Art
There are various electronic apparatuses provided with covers or display screens or viewers, such as mobile phones, notebooks, PDA, digital imagers and electronic books. The covers or display screens or viewers are pivotally mounted on the electronic apparatuses via pivot pins or rotary shafts, whereby the covers or display screens or viewers can be freely rotated and opened/closed under external force.
In order to operate the display module (such as the screen) and/or the apparatus body module of the electronic apparatus in more operation modes and application ranges, a dual-shaft mechanism is provided between the display module and the apparatus body module, whereby the display module and/or the apparatus body module can be operated in different operation modes by different rotational angles.
There is also a conventional mechanism composed of rollers and drive wires for transmitting force to the rotary shaft so as to rotate the rotary shaft. As known by those who are skilled in this field, during the operation process of the wires or the transmission belts, delay of kinetic energy transmission will take place. This is because the wires contact the rollers by points or lines or there is a gap between the wires and the rollers so that the wires are likely to slip or up and down deflect from the rollers. Under such circumstance, the wires will untruly operate to cause error. Also, the wires are made of elastic material and the fixing structure for assembling the wires with the rollers is not ideal. As a result, in force transmission, the load on the wires or the pulling force applied to the wires will increase. In this case, the transmission effect of the wires will be deteriorated and the wires may detach from the rollers. Especially, after a period of use, the force of the wires, which is preset in the assembling process will decrease due to elastic failure. Under such circumstance, the synchronous movement effect of the transmission mechanism will be deteriorated.
There is another problem existing in the application and manufacturing of the wires. That is, during the assembling process of the wires, the wires need to be tensioned. This will make it more difficult to control the quality of wiring and assembling. Therefore, the ratio of good products can be hardly promoted and the assembling time can be hardly shortened. As a result, the manufacturing cost is increased.
In order to improve the above problems, a conventional dual-shaft synchronous movement device has been developed. Such dual-shaft synchronous movement device employs multiple gears for transmitting force. However, as known by those who are skilled in this field, with the transmission gears, the gap between the shafts of the dual-shaft synchronous movement device can be hardly minified. Therefore, the entire transmission unit or structure will occupy a considerably large space. Especially, when the transmission unit is applied to a notebook or a miniaturized electronic device, the electronic device can hardly meet the requirement for lightweight and slimmed design. This is not what we expect.
The conventional rotary shaft structures and the relevant connection components thereof have some shortcomings in use and structural design that need to be overcome. It is therefore tried by the applicant to provide a dual-shaft synchronous movement device to eliminate the shortcomings existing in the conventional rotary shaft structure so as to widen the application range and facilitate the assembling process of the rotary shaft structures.
The dual-shaft synchronous movement device of the present invention has the following advantages:    1. The synchronous movement device of the present invention is mounted between the display module and the apparatus body module. When an operator 0°˜180° rotates the display module, the apparatus body module is synchronously relatively 0°˜180° rotated. Therefore, the total rotational angle of the display module and the apparatus body module is 360°. Accordingly, the operator can more quickly and conveniently operate the electronic apparatus in more operation modes (or application ranges). Also, the synchronous movement effect and operational stability of the synchronous movement device and the cooperative rotary shafts are enhanced.    2. The synchronous movement device of the present invention overcomes the problem of delay of kinetic energy transmission of the conventional wires. The synchronous movement device of the present invention also solves the problem of the conventional transmission mechanism that the wires contact the rollers by points or lines so that the wires are likely to slip or up and down deflect from the rollers and the wires will untruly operate to cause error. The synchronous movement device of the present invention also solves the problem of the conventional transmission mechanism that the fixing structure for assembling the wires with the rollers is not ideal so that in force transmission, the load on the wires or the pulling force applied to the wires will increase to deteriorate the transmission effect and the wires may detach from the rollers.    3. The synchronous movement device or transmission mechanism of the present invention is free from any gear for transmitting force as in the conventional technique. Therefore, the gap between the shafts can be as minified as possible. Therefore, the space occupied by the entire transmission unit or structure is reduced. Accordingly, when the transmission unit is applied to an electronic device, the electronic device can meet the requirement for lightweight and slimmed design.